Thread-safety in Maven builds

[madsop]

When running multithreaded Maven builds (with the -T param), I get warnings like

[WARNING] The following plugins are not marked @threadsafe in myModule:
[WARNING] se.ayoy.maven-plugins:ayoy-license-verifier-maven-plugin:1.1.0
[WARNING] Enable debug to see more precisely which goals are not marked @threadsafe.

[smuda]

It seems pretty simple to just add threadSafe=true to the Mojo but I'm unsure how to test that the plugin is really threadsafe.

[smuda]

Leaving references:
https://stackoverflow.com/questions/22133520/maven-thread-safe-plugin-pitfalls
https://cwiki.apache.org/confluence/display/MAVEN/Parallel+builds+in+Maven+3